Rock Island daily Argus. (Rock Island, Ill.) 1886-1893, 1887-10-20

TeIescope--Polishing with the Palm OF
the Hand-A Peep at Star-A
Story.
In lsS2 called to see Aivan Clark, the
distinguished constructor of Telescopes, who
has iust died ! found him at his home IN
Canbridgeport, Mass. His sons were busy
putting the flushing touches To the great
telescope object glass then being made for
the Russian Astronomical observatory at
Pnlkova The Puikoga objective was To lie
placed in Il temporary mounting that very
evening to bc tested lor tie first time on
celestial objects
1t Is i'll the after correction and perfecting
Of the objective which calls for the special
skill which has ma,ie Avian ClarE's name 50
famous. The large objectives, such as the
Pulkova and Lick glasses, are ground and
polished by machinery. Two levers work IN
opposite directions, aud are SO arranged thai
any part of the glasa surface may be reached,
doing the work Tue final polish, which is of
tine most delicate nature imaginable, is done
with the surface of the hand, Mr., Clark went
SO far as to say that one revolution of the
hand in excess would change the correction
On table was the finished PulkoHa lens,
which weighed 450 pounds and consiste of
=, !, 81 -. H. =; l;o,,t.
Generally these lenses are made to accurately
tit, and are Joined together with Canada bal
sam, but in such large glasses aSthe Pulkova
and the Lick, tEey are fitted IN a metal frame
,-i,, AZ, ,.ain.t,,a,t s thot tb.v can In. made
"a ,,rr,,acI aacb o,bar an. otbarvisa
Whan tI.,,.a,,ir,. was rf6,.;a,tlv advanced
,to ,o,t p, ,,tt,, tlo., .os ,I.,...j il, IT'S tam
-, t;,,i,,c, =; H. oo,,3a,, rhar, ,y.s mo
,,,,,,, .,i ~, larl,r..S WINS i,tansa The glass
,,ss hr,rt,It out IN . four vbeel hand trurk
.,I REL into ,b. ,,ha by f;,,a n,..n and f;yad
~, ,a,-oI,in,, If in the scrt.w tittipo Tn. tube
,-,s forrr Fl va foot limo and veiohed with The
atta,,I,rr fittings ,hnnt xavan toms Two niles
- b,i.r,,,t. s,,,,.,,r,.3 tho u,bola rbara
,,,.,.,,.,,r ,,,,,,,,o,,t o,,l ,Ie, ,.,,,h
as, o,,,,rat,Is was an,nIoyed the te,4scone was
,aisad and moved Nv 81 opida rome the mo.
ti,tp of an .,u.to,i,l movement h,.ino imi
,o,a3 h., ,,si,,1r ,.,,,,,,o,, uin3iaes A. ,ba
,i'l.,1 80, ,,,a L., - ,,.,ss
ara :, a., ,lIo.,.,,,,, ,t, .,i,s.,,.,-a,
-, ..f.I,,,,, y ,,.ba,, - .liol, I'm,
7F,t..,.,..ll... ,I,;.,.+ i,,,.,a,,, S,,,I,
,,,.,. ,,,.. ,,,.,t .,,.I,.,t ,s.J 70 t..s, ,t,i.
zen ,,n,, Ia,,
- -. - ,,,,-,,,,,,
me p'a''e'S ua' an >e.' anu ""n " ~ s'''
iSie'' WI" VIZ" VI " i'N''' ''''' i' ''A
eA''ile''' ""Je'' IVA '''''''S '"o "p'ic"i II
Ties "i q lT''S' nut Fe' '''T
WISE Hs Tue ''i st 'e'ss''ie van i,iihe i'i'
''iil' NNs''' V" n>'' ''a' u" u'7" ,'' w
seen merely spe'h "' iiEu'' luo stai 9e
'e'fei was siiiali one ana "HreS N'sio'e a
| pale minute OBJECT 'h i"'hi'H at 1t "i'i
ms "agh''i'tm instrument us "'"uefiu
| ieht gathering powers "ei" AT once eV'nellt NJ
| tor IN" Star s'i"he WIN VI" iuS'ef aiih uilii
| fancy "t an etertrl' hght IL was an "nJee
Which hr"nght "ht all Tue imler'Frt'"hs o
the glass, ana {" the ev'~ OF Mr. Iiark ah,
his SONS many were eNtieht' ana |" WAS sa'u
two n'"hths "'rk was necessary "' '"r'ec
them pullhg the 'ilai ''le i-''s were 'o"ere'
ami hNe men reN"s'e" Tue s'aSs III its h'i'''s
| Oh It's being pia'el III P'>iu"h again one
the sons was about 10 MAKE announcer test "oei
the old "iaii Nh"ntrn' "ait, h"Ss' let ne
e"oi'
| was curious I" h""" "na' 'n's 'oo'
mean, anu Ava o'aTA eNi'laii'eu 'nat TIE COZ
fectloh was 80 oeiica'e ihaC tie neat from III
ial'd7 oi the h'e men hou'''s ,'e i'ie'''i '''>
II the opJe'''>' ""u'" 'nai'se TUE cor ''''''i
5" II i'''i !" ''"''
IN cohNTISa''"i WIN "'' ''h'h o'i t'
advantages" "i i'i'iiie''Se so''i as '''
que, ne 'i''''''' '''''' c''' '''','' vi